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Purpose: To assess longitudinal changes in optical quality across the periphery (horizontal meridian, 60°) in young children who are at high (HR) or low risk (LR) of developing myopia, as well as a small subgroup of children who developed myopia over a 3-year time frame., Methods: Aberrations were measured every 6 months in 92 children with functional emmetropia at baseline. Children were classified into HR or LR based on baseline refractive error and parental myopia. Zernike polynomials were calculated for 4 mm pupils, accounting for the elliptical shape of the pupil in the periphery. Various metrics were computed, including Strehl Ratios with only high-order aberrations (HO-SR). Primary spherical aberration (SA), horizontal coma and defocus were also analysed given their relevance in emmetropisation. The areas under the image quality metrics for various regions of interest were computed., Results: HO-SR were higher in children at HR and children with myopia, even when SA was removed from the Strehl Ratio (SR) calculation. SA was less positive in children at HR and children with myopia. Defocus was more negative in children at HR and children with myopia at all eccentricities and was even more negative when computed relative to the fovea, an effect that increased in the mid periphery. Relative peripheral defocus also became more negative over time in children at HR and children with myopia at the mid temporal retina. The other aberrations showed no significant changes in time overall., Conclusions: This longitudinal study showed differences in HO-SR, SA and defocus in the central and near-peripheral retina (±20°) of young children at HR before they develop myopia compared with children at LR for myopia. The results may indicate these eccentricities are significant in providing signals for emmetropisation. The small changes noted over time may indicate that the differences are a cause of myopia development., (© 2025 The Author(s). Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)

Color vision assessment is essential in clinical practice, yet different tests exhibit distinct strengths and limitations. Here we apply a psychophysical paradigm, Angular Indication Measurement (AIM) for color detection and discrimination. AIM is designed to address some of the shortcomings of existing tests, such as prolonged testing time, limited accuracy and sensitivity, and the necessity for clinician oversight. AIM presents adaptively generated charts, each a N×M (here 4×4) grid of stimuli, and participants are instructed to indicate either the orientation of the gap in a cone-isolating Landolt C optotype or the orientation of the edge between two colors in an equiluminant color space. The contrasts or color differences of the stimuli are adaptively selected for each chart based on performance of prior AIM charts. In a group of 23 color-normal and 15 people with color vision deficiency (CVD), we validate AIM color against Hardy-Rand-Rittler (HRR), Farnsworth-Munsell 100 hue test (FM100), and anomaloscope color matching diagnosis and use machine learning techniques to classify the type and severity of CVD. The results show that AIM has classification accuracies comparable to that of the anomaloscope, and while HRR and FM100 are less accurate than AIM and an anomaloscope, HRR is very rapid. We conclude that AIM is a computer-based, self-administered, response-adaptive and rapid tool with high test-retest repeatability that has the potential to be suitable for both clinical and research applications., Competing Interests: Competing interests JS and PJB are founders of PerZeption Inc. JS and PJB are inventors of the AIM (Angular Indication Measurement) method, including AIM-Color detection and discrimination, which is patented (pending), owned by Northeastern University, Boston, USA, and exclusively licensed to PerZeption Inc. JH declares no competing interest.

Multistable perceptual phenomena provide insights into the mind's dynamic states within a stable external environment and the neural underpinnings of these consciousness changes are often studied with binocular rivalry. Conventional methods to study binocular rivalry suffer from biases and assumptions that limit their ability to describe the continuous nature of this perceptual transitions and to discover what kind of percept was perceived across time. In this study, we propose a novel way to avoid those shortcomings by combining a continuous psychophysical method that estimates introspection during binocular rivalry with machine learning clustering and transition probability analysis. This combination of techniques reveals individual variability and complexity of perceptual experience in 28 normally sighted participants. Also, the analysis of transition probabilities between perceptual categories, i.e., exclusive and different kinds of mixed percepts, suggest that interocular perceptual competition, triggered by low-level stimuli, involves conflict between monocular and binocular neural processing sites rather than mutual inhibition of monocular sites., Competing Interests: Competing interests InFoRM was invented by PJB and JS and is disclosed as patent (pending) held by Northeastern University, Boston USA.

Purpose: People with albinism (PwA) are known to have visual impairments; however, little is known about whether these functions are disrupted across earlier and later stages of the visual pathway. We investigated distinct perceptual functions and fixation stability within each observer and compared the data with age- (±5 years) and sex-matched controls., Methods: Twenty-one self-reported PwA and twenty-one controls were recruited. Angular-indication measurement (AIM) and foraging-interactive-D-prime (FInD) psychophysical methods were deployed to measure OS, OD, and OU near visual acuity, spatial contrast sensitivity function (CSF), temporal contrast sensitivity (tCS; 0.5 c/°; horizontal grating: 0, 1, 2, 4, and 8 Hz), OU glare acuity, threshold-versus-contrast (2c/° vertical grating), long, medium, and short wavelength cone-isolated color detection, color discrimination, stereoacuity across spatial frequencies (1c/°, 2c/°, 4c/°, 8c/°), horizontal, circular, radial pattern and motion coherence, and equivalent-noise motion detection. Thresholds were determined by AIM and FInD and compared using N-ANOVAs, t-tests, planned multi-comparisons, correlations, and unsupervised, agglomerative hierarchical cluster analysis for each group., Results: We found significant differences between groups for most visual functions except for simple and complex form-coherence (two way-ANOVAs, P > 0.05) and complex motion coherence. Correlations between outcomes revealed more significant correlations for PwA and differences in the specific correlates between groups. Unsupervised hierarchical clustering revealed different functional clusters between groups., Conclusions: AIM and FInD successfully interrogated visual deficits in PwA. Overall, PwA showed impaired performance in achromatic, chromatic, temporal, and binocular functions, and had higher intrinsic noise levels. Midlevel vision was comparable between groups. Unsupervised cluster analysis and correlation between outcomes revealed a difference in functional outcome clusters between groups. The results may help to increase the efficiency of screening and identify target deficits for rehabilitation.

Cerebral visual impairment (CVI) is a brain-based visual disorder associated with injury and/or maldevelopment of central visual pathways. Visuospatial processing impairments are a cardinal feature of the complex clinical profile of individuals with CVI. Here, we assessed visuospatial processing abilities using a classic conjunction search task. Twenty-three (23) individuals previously diagnosed with CVI (mean age 18.55 years ± 4.98 SD) and 37 controls with neurotypical development (mean age 21.11 years ± 4.56 SD) participated in the study. Subjects were instructed to search for a two-feature target (a white or black letter "O" or "C") presented among a varying number of surrounding distractors (set sizes ranging from 1 to 32 items). Behavioral outcomes collected were reaction time (RT), accuracy, as well as slope and intercept values derived from the RT x set size function. Overall, participants with CVI took longer and were less accurate in finding the target than controls. Analysis of RT x set size functions revealed a profile consistent with less efficient search and slower visual orienting responses as indexed by higher slope and intercept values, respectively. These results are consistent with clinical reports of impaired visuospatial processing abilities and deployment of visual selective attention in individuals with CVI.

Coordination of goal-directed behavior depends on the brain's ability to recover the locations of relevant objects in the world. In humans, the visual system encodes the spatial organization of sensory inputs, but neurons in early visual areas map objects according to their retinal positions, rather than where they are in the world. How the brain computes world-referenced spatial information across eye movements has been widely researched and debated. Here, we tested whether shifts of covert attention are sufficiently precise in space and time to track an object's real-world location across eye movements. We found that observers' attentional selectivity is remarkably precise and is barely perturbed by the execution of saccades. Inspired by recent neurophysiological discoveries, we developed an observer model that rapidly estimates the real-world locations of objects and allocates attention within this reference frame. The model recapitulates the human data and provides a parsimonious explanation for previously reported phenomena in which observers allocate attention to task-irrelevant locations across eye movements. Our findings reveal that visual attention operates in real-world coordinates, which can be computed rapidly at the earliest stages of cortical processing., Competing Interests: Competing interests statement:The authors declare no competing interest.

Significance: Angular Indication Measurement (AIM) is an adaptive, self-administered, and generalizable orientation-judgment method designed to interrogate visual functions. We introduce AIM Visual Acuity (VA) and show its features and outcome measures. Angular Indication Measurement VA's ability to detect defocus was comparable with that of an Early Treatment of Diabetic Retinopathy Study (ETDRS) letter chart and showed greater sensitivity to astigmatic blur., Purpose: This proof-of-concept study introduces Angular Indication Measurement and applies it to VA., Methods: First, we compared the ability of AIM-VA and ETDRS to detect defocus and astigmatic blur in 22 normally sighted adults. Spherical and cylindrical lenses in the dominant eye induced blur. Second, we compared repeatability over two tests of AIM-VA and ETDRS., Results: A repeated-measure analysis of variance showed a main effect for defocus blur and test. For the astigmatism experiment, an interaction between blur and orientation was found. Pairwise comparisons showed that AIM was more sensitive to astigmatic-induced VA loss than ETDRS. Bland-Altman plots showed small bias and no systematic learning effect for either test type and improved repeatability with more than two adaptive steps for AIM-VA., Conclusions: Angular Indication Measurement VA's ability to detect defocus was comparable with that of an ETDRS letter chart and showed greater sensitivity to induced astigmatic blur, and AIM-VA's repeatability is comparable with ETDRS when using two or more adaptive steps. Angular Indication Measurement's self-administered orientation judgment approach is generalizable to interrogate other visual functions, e.g., contrast, color, motion, and stereovision., Competing Interests: Conflict of Interest Disclosure: AIM is disclosed as patented (status pending during the time of submission) and held by Northeastern University, Boston, USA. JS and PJB are founders and shareholders of PerZeption Inc., which has an exclusive license agreement for AIM. All other authors declare no conflict of interests., (Copyright © 2024 American Academy of Optometry.)

Purpose: Stereopsis is a critical visual function, however clinical stereotests are time-consuming, coarse in resolution, suffer memorization artifacts, poor repeatability, and low agreement with other tests. Foraging Interactive D-prime (FInD) Stereo and Angular Indication Measurement (AIM) Stereo were designed to address these problems. Here, their performance was compared with 2-Alternative-Forced-Choice (2-AFC) paradigms (FInD Stereo only) and clinical tests (Titmus and Randot) in 40 normally-sighted and 5 binocularly impaired participants (FInD Stereo only)., Methods: During FInD tasks, participants indicated which cells in three 4*4 charts of bandpass-filtered targets (1,2,4,8c/° conditions) contained depth, compared with 2-AFC and clinical tests. During the AIM task, participants reported the orientation of depth-defined bars in three 4*4 charts. Stereoscopic disparity was adaptively changed after each chart. Inter-test agreement, repeatability and duration were compared., Results: Test duration was significantly longer for 2-AFC (mean = 317s;79s per condition) than FInD (216s,18s per chart), AIM (179s, 60s per chart), Titmus (66s) or RanDot (97s). Estimates of stereoacuity differed across tests and were higher by a factor of 1.1 for AIM and 1.3 for FInD. No effect of stimulus spatial frequency was found. Agreement among tests was generally low (R2 = 0.001 to 0.24) and was highest between FInD and 2-AFC (R2 = 0.24;p<0.01). Stereoacuity deficits were detected by all tests in binocularly impaired participants., Conclusions: Agreement among all tests was low. FInD and AIM inter-test agreement was comparable with other methods. FInD Stereo detected stereo deficits and may only require one condition to identify these deficits. AIM and FInD are response-adaptive, self-administrable methods that can estimate stereoacuity reliably within one minute., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: FInD and AIM technologies are disclosed as provisional patented (AIM) and pending patent (FInD) and held by Northeastern University, Boston, USA. FInD title: Method for visual function assessment; Application PCT/US2021/049250 AIM title: Self-administered adaptive vision screening test using angular indication; Application PCT/US2023/012959 JS and PJB are founders and shareholders of PerZeption Inc, which has an exclusive license agreement for FInD and AIM with Northeastern University. SN declares that she has no conflict of interest. This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2024 Neupane et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Visuospatial processing impairments are prevalent in individuals with cerebral visual impairment (CVI) and are typically ascribed to "dorsal stream dysfunction" (DSD). However, the contribution of other cortical regions, including early visual cortex (EVC), frontal cortex, or the ventral visual stream, to such impairments remains unknown. Thus, here, we examined fMRI activity in these regions, while individuals with CVI (and neurotypicals) performed a visual search task within a dynamic naturalistic scene. First, behavioral performance was measured with eye tracking. Participants were instructed to search and follow a walking human target. CVI participants took significantly longer to find the target, and their eye gaze patterns were less accurate and less precise. Second, we used the same task in the MRI scanner. Along the dorsal stream, activation was reduced in CVI participants, consistent with the proposed DSD in CVI. Intriguingly, however, visual areas along the ventral stream showed the complete opposite pattern, with greater activation in CVI participants. In contrast, we found no differences in either EVC or frontal cortex between groups. These results suggest that the impaired visuospatial processing abilities in CVI are associated with differential recruitment of the dorsal and ventral visual streams, likely resulting from impaired selective attention., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: Individuals with amblyopia experience central vision deficits, including loss of visual acuity, binocular vision, and stereopsis. In this study, we examine the differences in peripheral binocular imbalance in children with anisometropic amblyopia, strabismic amblyopia, and typical binocular vision to determine if there are systematic patterns of deficits across the visual field., Methods: This prospective cohort study recruited 12 participants with anisometropic amblyopia, 10 with strabismic amblyopia, and 10 typically sighted controls (age range, 5-18 years). Binocular imbalance was tested at 0°, 4°, and 8° eccentricities (4 angular locations each) using band-pass filtered Auckland optotypes (5 cycles per optotype) dichoptically presented with differing contrast to each eye. The interocular contrast ratio was adjusted until the participant reported each optotype with equal frequency., Results: Participants with anisometropic and strabismic amblyopia had a more balanced contrast ratio, or decreased binocular imbalance, at 4° and 8° eccentricities as compared with central vision. Participants with strabismic amblyopia had significantly more binocular imbalance in the periphery as compared with individuals with anisometropic amblyopia or controls. A linear mixed effects model showed a main effect for strabismic amblyopia and eccentricity on binocular imbalance across the visual field., Conclusions: There is evidence of decreased binocularity deficits, or interocular suppression, in the periphery in anisometropic and strabismic amblyopia as compared with controls. Notably, those with strabismic amblyopia exhibited more significant peripheral binocular imbalance. These variations in binocularity across the visual field among different amblyopia subtypes may necessitate tailored approaches for dichoptic treatment.

We investigated the relative influence of image salience and image semantics during the visual search of naturalistic scenes, comparing performance in individuals with cerebral visual impairment (CVI) and controls with neurotypical development. Participants searched for a prompted target presented as either an image or text cue. Success rate and reaction time were collected, and gaze behavior was recorded with an eye tracker. A receiver operating characteristic (ROC) analysis compared the distribution of individual gaze landings based on predictions of image salience (using Graph-Based Visual Saliency) and image semantics (using Global Vectors for Word Representations combined with Linguistic Analysis of Semantic Salience) models. CVI participants were less likely and were slower in finding the target. Their visual search behavior was also associated with a larger visual search area and greater number of fixations. ROC scores were also lower in CVI compared to controls for both model predictions. Furthermore, search strategies in the CVI group were not affected by cue type, although search times and accuracy showed a significant correlation with verbal IQ scores for text-cued searches. These results suggest that visual search patterns in CVI are driven mainly by image salience and provide further characterization of higher-order processing deficits observed in this population., (© 2024. The Author(s).)

Colour vision deficiencies (CVDs) indicate potential genetic variations and can be important biomarkers of acquired impairment in many neuro-ophthalmic diseases. However, CVDs are typically measured with tests which possess high sensitivity for detecting the presence of a CVD but do not quantify its type or severity. In this study, we introduce Foraging Interactive D-prime (FInD), a novel computer-based, generalisable, rapid, self-administered vision assessment tool and apply it to colour vision testing. This signal detection theory-based adaptive paradigm computed test stimulus intensity from d-prime analysis. Stimuli were chromatic Gaussian blobs in dynamic luminance noise, and participants clicked on cells that contained chromatic blobs (detection) or blob pairs of differing colours (discrimination). Sensitivity and repeatability of FInD colour tasks were compared against the Hardy-Rand-Rittler and the Farnsworth-Munsell 100 hue tests in 19 colour-normal and 18 inherited colour-atypical, age-matched observers. Rayleigh colour match was also completed. Detection and discrimination thresholds were higher for atypical than for typical observers, with selective threshold elevations corresponding to unique CVD types. Classifications of CVD type and severity via unsupervised machine learning confirmed functional subtypes. FInD tasks reliably detect inherited CVDs, and may serve as valuable tools in basic and clinical colour vision science., (© 2023 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)

Aim: Using a visual psychophysical paradigm, we sought to assess motion and form coherence thresholds as indices of dorsal and ventral visual stream processing respectively, in individuals with cerebral visual impairment (CVI). We also explored potential associations between psychophysical assessments and brain lesion severity in CVI., Method: Twenty individuals previously diagnosed with CVI (mean age = 17 years 11 months [SD 5 years 10 months]; mean Verbal IQ = 86.42 [SD 35.85]) and 30 individuals with neurotypical development (mean age = 20 years 1 month [SD 3 years 8 months]; mean Verbal IQ = 110.05 [SD 19.34]) participated in the study. In this two-group comparison, cross-sectional study design, global motion, and form pattern coherence thresholds were assessed using a computerized, generalizable, self-administrable, and response-adaptive psychophysical paradigm called FInD (Foraging Interactive D-prime)., Results: Consistent with dorsal stream dysfunction, mean global motion (but not form) coherence thresholds were significantly higher in individuals with CVI compared to controls. No statistically significant association was found between coherence thresholds and lesion severity., Interpretation: These results suggest that the objective assessment of motion and form coherence threshold sensitivities using this psychophysical paradigm may be useful in helping to characterize perceptual deficits and the complex clinical profile of CVI., What This Paper Adds: In participants with cerebral visual impairment (CVI), motion (but not form) coherence thresholds were significantly higher compared to controls. These psychophysical results support the notion of dorsal stream dysfunction in CVI., (© 2023 Mac Keith Press.)

Crowding occurs when the presence of nearby features causes highly visible objects to become unrecognizable. Although crowding has implications for many everyday tasks and the tremendous amounts of research reflect its importance, surprisingly little is known about how depth affects crowding. Most available studies show that stereoscopic disparity reduces crowding, indicating that crowding may be relatively unimportant in three-dimensional environments. However, most previous studies tested only small stereoscopic differences in depth in which disparity, defocus blur, and accommodation are inconsistent with the real world. Using a novel multi-depth plane display, this study investigated how large (0.54-2.25 diopters), real differences in target-flanker depth, representative of those experienced between many objects in the real world, affect crowding. Our findings show that large differences in target-flanker depth increased crowding in the majority of observers, contrary to previous work showing reduced crowding in the presence of small depth differences. Furthermore, when the target was at fixation depth, crowding was generally more pronounced when the flankers were behind the target as opposed to in front of it. However, when the flankers were at fixation depth, crowding was generally more pronounced when the target was behind the flankers. These findings suggest that crowding from clutter outside the limits of binocular fusion can still have a significant impact on object recognition and visual perception in the peripheral field., Competing Interests: SS, YS, JA, PB No competing interests declared, (© 2023, Smithers et al.)

Individuals with cerebral visual impairment (CVI) have difficulties identifying common objects, especially when presented as cartoons or abstract images. In this study, participants were shown a series of images of ten common objects, each from five possible categories ranging from abstract black & white line drawings to color photographs. Fifty individuals with CVI and 50 neurotypical controls verbally identified each object and success rates and reaction times were collected. Visual gaze behavior was recorded using an eye tracker to quantify the extent of visual search area explored and number of fixations. A receiver operating characteristic (ROC) analysis was also carried out to compare the degree of alignment between the distribution of individual eye gaze patterns and image saliency features computed by the graph-based visual saliency (GBVS) model. Compared to controls, CVI participants showed significantly lower success rates and longer reaction times when identifying objects. In the CVI group, success rate improved moving from abstract black & white images to color photographs, suggesting that object form (as defined by outlines and contours) and color are important cues for correct identification. Eye tracking data revealed that the CVI group showed significantly greater visual search areas and number of fixations per image, and the distribution of eye gaze patterns in the CVI group was less aligned with the high saliency features of the image compared to controls. These results have important implications in helping to understand the complex profile of visual perceptual difficulties associated with CVI., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Clinical Relevance: Horizontal fusional reserves are used in the diagnosis and monitoring of common vergence disorders, such as convergence insufficiency, which can cause asthenopia and impact near work. Infrared eyetracking technology shows promise for obtaining automated and objective measurements of fusional reserves, expanding options for screening, clinical testing, and at-home monitoring/vision training., Background: Current clinical tests for fusional reserves rely on subjective judgements made by patients (for diplopia) and clinicians (for eye movements). This paper describes an objective and automated "digital fusion-range test" pilot-tested in adults without current eye disease or binocular vision anomalies. This test combines a consumer-grade infrared eyetracker, a dichoptic display, and custom analyses programs to measure convergence and divergence reserves., Methods: Twenty-nine adult participants completed the study. Horizontal fusional reserves at 55 cm were measured using prism bars and with our computer-based digital fusion-range test. For the digital test, observers viewed dichoptic targets whose binocular disparity modulated over time (at speeds of 0.5, 1.0, or 2.0 Δ/s) while their eye movements were continuously recorded. Subjective reports of break and recovery (by keyboard button press) were compared to objective estimates extracted from eyetracking recordings (via automated analyses)., Results: Objective and subjective measures of break and recovery agreed closely. Clinically small (0.3-2Δ) but statistically significant (p < 0.012) differences were found between measurement types for divergence breaks/recoveries and convergence recoveries. No significant differences were found for convergence breaks (p = 0.11). Such differences are consistent with an average 0.91 (SD 1.66) seconds delay between objective break/recovery and subjective responses. The digital test produced comparable results to the standard clinical prism bar method., Conclusion: The digital fusion-range test supports an automated, reliable assessment of horizontal fusional reserves, which do not depend on subjective responses. This technology may prove useful in a variety of clinical and community-based settings.

Human visual experience usually provides ample opportunity to accumulate knowledge about events unfolding in the environment. In typical scene perception experiments, however, participants view images that are unrelated to each other and, therefore, they cannot accumulate knowledge relevant to the upcoming visual input. Consequently, the influence of such knowledge on how this input is processed remains underexplored. Here, we investigated this influence in the context of gaze control. We used sequences of static film frames arranged in a way that allowed us to compare eye movements to identical frames between two groups: a group that accumulated prior knowledge relevant to the situations depicted in these frames and a group that did not. We used a machine learning approach based on hidden Markov models fitted to individual scanpaths to demonstrate that the gaze patterns from the two groups differed systematically and, thereby, showed that recently accumulated prior knowledge contributes to gaze control. Next, we leveraged the interpretability of hidden Markov models to characterize these differences. Additionally, we report two unexpected and interesting caveats of our approach. Overall, our results highlight the importance of recently acquired prior knowledge for oculomotor control and the potential of hidden Markov models as a tool for investigating it.

This proof-of-concept study introduces Angular Indication Measurement and applies it to VA (AIM-VA). First, we compared the ability of AIM-VA and ETDRS to detect defocus and astigmatic blur in 22 normally-sighted adults. Spherical and cylindrical lenses (±0.00D, +0.25D, +0.50D, +0.75D, +1.00D, +2.00D and +0.50D, +1.00D, +2.00D each at 0°, 90°, 135°, respectively) in the dominant eye induced blur. Second, we compared repeatability over two tests of AIM-VA and ETDRS. A 2-way-ANOVA showed a main effect for defocus-blur and test with no interaction. A 3-way-ANOVA for the astigmatism experiment revealed main effects for test type, blur, and direction and with no interactions. Planned multiple comparisons showed AIM had greater astigmatic-induced VA loss than ETDRS. Bland-Altman plots showed small bias and no systematic learning effect for either test type and improved repeatability with >2 adaptive steps for AIM-VA. AIM-VA's ability to detect defocus was comparable with that of an ETDRS letter chart and showed greater sensitivity to astigmatic blur, and AIM-VA's repeatability is comparable with ETDRS when using 2 or more adaptive steps. AIM's self-administered orientation judgment approach is generalizable to interrogate other visual functions, e.g., contrast, color, motion, stereo-vision.

Background: Keratoconus is associated with thinning and anterior protrusion of the cornea resulting in the symptoms of blurry and distorted vision. The commonly used clinical vision tests such as visual acuity and contrast sensitivity may not reflect the symptoms experienced in keratoconus and there are no quantitative tools to measure visual distortion. In this study, we used a quantitative test based on vernier alignment and field matching techniques to quantify visual distortion in keratoconus and assess its relation to corneal structural changes., Methods: A total of 50 participants (25 keratoconus and 25 visually normal) completed the experiment where they aligned supra-threshold white target circles in opposite field in reference to guidelines and circles to complete a square structure monocularly. The task was repeated five times and the global distortion index (GDI) and global uncertainty index (GUI) were calculated as the mean and standard deviation respectively of local perceived misalignment of target circles over five trials., Results: Both GDI and GUI were higher in participants with keratoconus compared to controls (p < 0.01). Both parameters correlated with the best corrected visual acuity, maximum corneal curvature (K max ), topographical keratoconus classification (TKC) and central corneal thickness (CCT)., Conclusion: Our findings show that the quantitative measure of distortion could be a useful tool for behavioural assessment of progressive keratoconus., (© 2022. The Author(s), under exclusive licence to The Royal College of Ophthalmologists.)

Purpose: We used baseline data from the PICNIC longitudinal study to investigate structural, functional, behavioural and heritable metrics that may predict future myopia in young children., Methods: Cycloplegic refractive error (M) and optical biometry were obtained in 97 young children with functional emmetropia. Children were classified as high risk (HR) or low risk (LR) for myopia based on parental myopia and M. Other metrics included axial length (AXL), axial length/corneal radius (AXL/CR) and refractive centile curves., Results: Based on the PICNIC criteria, 46 children (26 female) were classified as HR (M = +0.62 ± 0.44 D, AXL = 22.80 ± 0.64 mm) and 51 (27 female) as LR (M = +1.26 ± 0.44 D, AXL = 22.77 ± 0.77 mm). Based on centiles, 49 children were HR, with moderate agreement compared with the PICNIC classification (k = 0.65, p < 0.01). ANCOVA with age as a covariate showed a significant effect for AXL (p < 0.01), with longer AXL and deeper anterior chamber depth (ACD) (p = 0.01) in those at HR (differences AXL = 0.16 mm, ACD = 0.13 mm). Linear regression models showed that central corneal thickness (CCT), ACD, posterior vitreous depth (PVD) (=AXL - CCT - ACD-lens thickness (LT)), corneal radius (CR) and age significantly predicted M (R = 0.64, p < 0.01). Each 1.00 D decrease in hyperopia was associated with a 0.97 mm elongation in PVD and 0.43 mm increase in CR. The ratio AXL/CR significantly predicted M (R = -0.45, p < 0.01), as did AXL (R = -0.25, p = 0.01), although to a lesser extent., Conclusions: Although M and AXL were highly correlated, the classification of pre-myopic children into HR or LR was significantly different when using each parameter, with AXL/CR being the most predictive metric. At the end of the longitudinal study, we will be able to assess the predictability of each metric., (© 2023 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.)

Individuals with cerebral visual impairment (CVI) frequently report challenges with face recognition, and subsequent difficulties with social interactions. However, there is limited empirical evidence supporting poor face recognition in individuals with CVI and the potential impact on social-emotional quality-of-life factors. Moreover, it is unclear whether any difficulties with face recognition represent a broader ventral stream dysfunction. In this web-based study, data from a face recognition task, a glass pattern detection task, and the Strengths and Difficulties Questionnaire (SDQ) were analyzed from 16 participants with CVI and 25 controls. In addition, participants completed a subset of questions from the CVI Inventory to provide a self-report of potential areas of visual perception that participants found challenging. The results demonstrate a significant impairment in the performance of a face recognition task in participants with CVI compared to controls, which was not observed for the glass pattern task. Specifically, we observed a significant increase in threshold, reduction in the proportion correct, and an increase in response time for the faces, but not for the glass pattern task. Participants with CVI also reported a significant increase in sub-scores of the SDQ for emotional problems and internalizing scores after adjusting for the potential confounding effects of age. Finally, individuals with CVI also reported a greater number of difficulties on items from the CVI Inventory, specifically the five questions and those related to face and object recognition. Together, these results indicate that individuals with CVI may demonstrate significant difficulties with face recognition, which may be linked to quality-of-life factors. This evidence suggests that targeted evaluations of face recognition are warranted in all individuals with CVI, regardless of their age.

Perceptual multistability, e.g. Binocular Rivalry, has been intensively used as a tool to study visual consciousness. Current methods to assess multistability do not capture all potentially occurring perceptual states, provide no estimate of introspection, and lack continuous, high-temporal resolution to resolve perceptual changes between states and within mixed perceptual states. We introduce InFoRM (Indicate-Follow-Replay-Me), a four-phase method that (1) trains a participant to self-generate estimates of perceptual introspection-maps that are (2) validated during a physical mimic task, (3) gathers perceptual multistability data, and (4) confirms their validity during a physical replay. 28 condition-blinded adults performed InFoRM while experiencing binocular rivalry evoked with orthogonal sinusoidal gratings. A 60 Hz joystick (3600 data samples/minute) was used to indicate continuously changes across six perceptual states within each 1 min trial. A polarized monitor system was used to present the stimuli dichoptically. Three contrast conditions were investigated: low vs low, high vs high, and low vs high. InFoRM replicates standard outcome measures, i.e. alternation rate, mean and relative proportions of perception, and distribution of exclusive percepts that are well fitted with gamma functions. Furthermore, InFoRM generates novel outcomes that deliver new insights in visual cognition via estimates of introspection maps, in ocular dominance via perceptual-state-specific dominance scores, in transitory dynamics between and within perceptual states, via techniques adopted from eye-tracking, and in rivalry-zone-size estimates utilizing InFoRM's ability to simulate piecemeal perception. The replay phase (physical replay of perceptual rivalry) confirmed good overall agreement (73% ±5 standard deviation). InFoRM can be applied to other multistable paradigms and can be used to study visual consciousness in typical and neuro-atypical populations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Sensory differences between autism and neuro-typical populations are well-documented and have often been explained by either weak-central-coherence or excitation/inhibition-imbalance cortical theories. We tested these theories with perceptual multi-stability paradigms in which dissimilar images presented to each eye generate dynamic cyclopean percepts based on ongoing cortical grouping and suppression processes. We studied perceptual multi-stability with Interocular Grouping (IOG), which requires the simultaneous integration and suppression of image fragments from both eyes, and Conventional Binocular Rivalry (CBR), which only requires global suppression of either eye, in 17 autistic adults and 18 neurotypical participants. We used a Hidden-Markov-Model as tool to analyze the multistable dynamics of these processes. Overall, the dynamics of multi-stable perception were slower (i.e. there were longer durations and fewer transitions among perceptual states) in the autistic group compared to the neurotypical group for both IOG and CBR. The weighted Markovian transition distributions revealed key differences between both groups and paradigms. The results indicate overall lower levels of suppression and decreased levels of grouping in autistic than neurotypical participants, consistent with elements of excitation/inhibition imbalance and weak-central-coherence theories., (© 2022. The Author(s).)

The sensitivity of the human visual system is thought to be shaped by environmental statistics. A major endeavor in vision science, therefore, is to uncover the image statistics that predict perceptual and cognitive function. When searching for targets in natural images, for example, it has recently been proposed that target detection is inversely related to the spatial similarity of the target to its local background. We tested this hypothesis by measuring observers' sensitivity to targets that were blended with natural image backgrounds. Targets were designed to have a spatial structure that was either similar or dissimilar to the background. Contrary to masking from similarity, we found that observers were most sensitive to targets that were most similar to their backgrounds. We hypothesized that a coincidence of phase alignment between target and background results in a local contrast signal that facilitates detection when target-background similarity is high. We confirmed this prediction in a second experiment. Indeed, we show that, by solely manipulating the phase of a target relative to its background, the target can be rendered easily visible or undetectable. Our study thus reveals that, in addition to its structural similarity, the phase of the target relative to the background must be considered when predicting detection sensitivity in natural images.

Purpose: Dynamic text presentation methods may improve reading ability in patients with central vision loss (CVL) by eliminating the need for accurate eye movements. We compared rapid serial visual presentation (RSVP) and horizontal scrolling text presentation (scrolling) on reading rate and reading acuity in CVL observers and normally-sighted controls with simulated CVL (simCVL)., Methods: CVL observers' (n = 11) central scotomas and preferred retinal loci (PRL) for each eye were determined with MAIA microperimetry and fixation analysis. SimCVL controls (n = 16) used 4° inferior eccentric viewing, enforced with an Eyelink eye-tracker. Observers read aloud 4-word phrases randomly drawn from the MNREAD sentences. Six font sizes (0.50-1.30 logMAR) were tested with the better near acuity eye and both eyes of CVL observers. Three font sizes (0.50-1.00 logMAR) were tested binocularly in simCVL controls. Text presentation duration of each word for RSVP or drift speed for scrolling was varied to determine reading rate, defined as 50% of words read correctly. In a subset of CVL observers (n = 7), relationships between PRL eccentricity, reading threshold and rate were explored., Results: SimCVL controls demonstrated significantly faster reading rates for RSVP than scrolling text (p < 0.0001), and there was a significant main effect of font size (p < 0.0001). CVL patients demonstrated no significant differences in binocular reading rate between font sizes (p = 0.12) and text presentation (p = 0.25). Similar results were seen under monocular conditions. Reading acuity for RSVP and scrolling worsened with increasing PRL eccentricity (μ = 4.5°, p = 0.07). RSVP reading rate decreased significantly with increasing eccentricity (p = 0.02)., Conclusions: Consistent with previous work, reading acuity worsened with increasing PRL eccentricity. RSVP and scrolling text presentations significantly affected reading rate in simCVL, but not in CVL observers, suggesting that simCVL results may not generalise to pathological CVL., (© 2021 The Authors Ophthalmic and Physiological Optics © 2021 The College of Optometrists.)

Individuals with cerebral visual impairment (CVI) often present with deficits related to visuospatial processing. However, the neurophysiological basis underlying these higher order perceptual dysfunctions have not been clearly identified. We assessed visual search performance using a novel virtual reality based task paired with eye tracking to simulate the exploration of a naturalistic scene (a virtual toy box). This was combined with electroencephalography (EEG) recordings and an analysis pipeline focusing on time frequency decomposition of alpha oscillatory activity. We found that individuals with CVI showed an overall impairment in visual search performance (as indexed by decreased success rate, as well as increased reaction time, visual search area, and gaze error) compared to controls with neurotypical development. Analysis of captured EEG activity following stimulus onset revealed that in the CVI group, there was a distinct lack of strong and well defined posterior alpha desynchronization; an important signal involved in the coordination of neural activity related to visual processing. Finally, an exploratory analysis revealed that in CVI, the magnitude of alpha desynchronization was associated with impaired visual search performance as well as decreased volume of specific thalamic nuclei implicated in visual processing. These results suggest that impairments in visuospatial processing related to visual search in CVI are associated with alterations in alpha band oscillations as well as early neurological injury at the level of visual thalamic nuclei., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Purpose: The purpose of this study was to evaluate retinal responses to different types and magnitudes of simulated optical blur presented at specific retinal eccentricities using naturalistic images., Methods: Electroretinograms (ERGs) were recorded from 27 adults using 30-degree dead leaves naturalistic images, digitally blurred with one of three types of optical blur (defocus, astigmatism, and spherical aberrations), and one of three magnitudes (0.1, 0.3, or 0.5 µm) of blur. Digitally computed blur was applied to the entire image, or on an area outside the central 6 degrees or 12 degrees of retinal eccentricity., Results: ERGs were significantly affected by blur type, magnitude, and retinal eccentricity. ERGs were differentially affected by defocus and spherical aberrations; however, astigmatism had no effect on the ERGs. When blur was applied only beyond the central 12 degrees eccentricity, the ERGs were unaffected. However, when blur was applied outside the central 6 degrees, the ERG responses were significantly reduced and were no different from the ERGs recorded with entirely blurred images., Conclusions: Blur type, magnitude, and location all affect the retinal responses. Our data indicate that the retinal area between 6 and 12 degrees eccentricity has the largest effect on the retinal responses to blur. In addition, certain optical blur types appear to have a more detrimental effect on the ERGs than others. These results cannot be solely explained by changes to image contrast and spatial frequency content, suggesting that retinal neurons might be sensitive to spatial cues in order to differentiate between different blur types.

Purpose: To model the global test-retest variability of visual fields (VFs) in glaucoma., Design: Retrospective cohort study., Participants: Test-retest VFs from 4044 eyes of 4044 participants., Methods: We selected 2 reliable VFs per eye measured with the Humphrey Field Analyzer (Swedish interactive threshold algorithm 24-2) within 30 days of each other. Each VF had fixation losses (FLs) of 33% or less, false-negative results (FNRs) of 20% or less, and false-positive results (FPRs) of 20% or less. Stepwise linear regression was applied to select the model best predicting the global test-retest variability from 3 categories of features of the first VF: (1) base parameters (age, mean deviation, pattern standard deviation, glaucoma hemifield test results, FPR, FNR, and FL); (2) total deviation (TD) at each location; and (3) computationally derived archetype VF loss patterns. The global test-retest variability was defined as root mean square deviation (RMSD) of TD values at all 52 VF locations., Main Outcome Measures: Archetype models to predict the global test-retest variability., Results: The mean ± standard deviation of the root mean square deviation was 4.39 ± 2.55 dB. Between the 2 VF tests, TD values were correlated more strongly in central than in peripheral VF locations (intraclass coefficient, 0.66-0.89; P < 0.001). Compared with the model using base parameters alone (adjusted R 2  = 0.45), adding TD values improved prediction accuracy of the global variability (adjusted R 2  = 0.53; P < 0.001; Bayesian information criterion [BIC] decrease of 527; change of >6 represents strong improvement). Lower TD sensitivity in the outermost peripheral VF locations was predictive of higher global variability. Adding archetypes to the base model improved model performance with an adjusted R 2 of 0.53 (P < 0.001) and lowering of BIC by 583. Greater variability was associated with concentric peripheral defect, temporal hemianopia, inferotemporal defect, near total loss, superior peripheral defect, and central scotoma (listed in order of decreasing statistical significance), and less normal VF results and superior paracentral defect., Conclusions: Inclusion of archetype VF loss patterns and TD values based on first VF improved the prediction of the global test-retest variability than using traditional global VF indices alone., (Copyright © 2020 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Myopia has been discussed as a risk factor for glaucoma. In this study, we characterized the relationship between ametropia and patterns of visual field (VF) loss in glaucoma. Reliable automated VFs (SITA Standard 24-2) of 120,019 eyes from 70,495 patients were selected from five academic institutions. The pattern deviation (PD) at each VF location was modeled by linear regression with ametropia (defined as spherical equivalent (SE) starting from extreme high myopia), mean deviation (MD), and their interaction (SE × MD) as regressors. Myopia was associated with decreased PD at the paracentral and temporal VF locations, whereas hyperopia was associated with decreased PD at the Bjerrum and nasal step locations. The severity of VF loss modulated the effect of ametropia: with decreasing MD and SE, paracentral/nasal step regions became more depressed and Bjerrum/temporal regions less depressed. Increasing degree of myopia was positively correlated with VF depression at four central points, and the correlation became stronger with increasing VF loss severity. With worsening VF loss, myopes have increased VF depressions at the paracentral and nasal step regions, while hyperopes have increased depressions at the Bjerrum and temporal locations. Clinicians should be aware of these effects of ametropia when interpreting VF loss.

We effortlessly interact with objects in our environment, but how do we know where something is? An object's apparent position does not simply correspond to its retinotopic location but is influenced by its surrounding context. In the natural environment, this context is highly complex, and little is known about how visual information in a scene influences the apparent location of the objects within it. We measured the influence of local image statistics (luminance, edges, object boundaries, and saliency) on the reported location of a brief target superimposed on images of natural scenes. For each image statistic, we calculated the difference between the image value at the physical center of the target and the value at its reported center, using observers' cursor responses, and averaged the resulting values across all trials. To isolate image-specific effects, difference scores were compared to a randomly-permuted null distribution that accounted for any response biases. The observed difference scores indicated that responses were significantly biased toward darker regions, luminance edges, object boundaries, and areas of high saliency, with relatively low shared variance among these measures. In addition, we show that the same image statistics were associated with observers' saccade errors, despite large differences in response time, and that some effects persisted when high-level scene processing was disrupted by 180° rotations and color negatives of the originals. Together, these results provide evidence for landmark effects within natural images, in which feature location reports are pulled toward low- and high-level informative content in the scene.

Daily activities require the constant searching and tracking of visual targets in dynamic and complex scenes. Classic work assessing visual search performance has been dominated by the use of simple geometric shapes, patterns, and static backgrounds. Recently, there has been a shift toward investigating visual search in more naturalistic dynamic scenes using virtual reality (VR)-based paradigms. In this direction, we have developed a first-person perspective VR environment combined with eye tracking for the capture of a variety of objective measures. Participants were instructed to search for a preselected human target walking in a crowded hallway setting. Performance was quantified based on saccade and smooth pursuit ocular motor behavior. To assess the effect of task difficulty, we manipulated factors of the visual scene, including crowd density (i.e., number of surrounding distractors) and the presence of environmental clutter. In general, results showed a pattern of worsening performance with increasing crowd density. In contrast, the presence of visual clutter had no effect. These results demonstrate how visual search performance can be investigated using VR-based naturalistic dynamic scenes and with high behavioral relevance. This engaging platform may also have utility in assessing visual search in a variety of clinical populations of interest.

Purpose: To evaluate the performance of the quantitative visual acuity (qVA) method in measuring the visual acuity (VA) behavioral function., Methods: We evaluated qVA performance in terms of the accuracy, precision, and efficiency of the estimated VA threshold and range in Monte Carlo simulations and a psychophysical experiment. We also compared the estimated VA threshold from the qVA method with that from the Electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) and Freiburg Visual Acuity Text (FrACT) methods. Four repeated measures with all three methods were conducted in four Bangerter foil conditions in 14 eyes., Results: In both simulations and psychophysical experiment, the qVA method quantified the full acuity behavioral function with two psychometric parameters (VA threshold and VA range) with virtually no bias and with high precision and efficiency. There was a significant correlation between qVA estimates of VA threshold and range in the psychophysical experiment. In addition, qVA threshold estimates were highly correlated with those from the E-ETDRS and FrACT methods., Conclusions: The qVA method can provide an accurate, precise, and efficient assessment of the full acuity behavioral function with both VA threshold and range., Translational Relevance: The qVA method can accurately, precisely, and efficiently assess the full VA behavioral function. Further research will evaluate the potential value of these rich measures for both clinical research and patient care., Competing Interests: Disclosure: Y. Zhao, None; L.A. Lesmes, Adaptive Sensory Technology (E, I), Patent Nos. US 10758120B2, US 7938538, WO 201370091, PCT/US2015/028657 (P); M. Dorr, Adaptive Sensory Technology (E, I), Patent Nos. US 7938538, WO 201370091, PCT/US2015/028657 (P); P.J. Bex, Adaptive Sensory Technology (I), Patent Nos. US 7938538, WO 201370091, PCT/US2015/028657 (P); Z.-L. Lu, Adaptive Sensory Technology (I), Patent Nos. US 7938538, WO 201370091, PCT/US2015/028657 (P), (Copyright 2021 The Authors.)

Cerebral visual impairment (CVI) is associated with a wide range of visual perceptual deficits including global motion processing. However, the underlying neurophysiological basis for these impairments remain poorly understood. We investigated global motion processing abilities in individuals with CVI compared to neurotypical controls using a combined behavioral and multi-modal neuroimaging approach. We found that CVI participants had a significantly higher mean motion coherence threshold (determined using a random dot kinematogram pattern simulating optic flow motion) compared to controls. Using functional magnetic resonance imaging (fMRI), we investigated activation response profiles in functionally defined early (i.e. primary visual cortex; area V1) and higher order (i.e. middle temporal cortex; area hMT+) stages of motion processing. In area V1, responses to increasing motion coherence were similar in both groups. However, in the CVI group, activation in area hMT+ was significantly reduced compared to controls, and consistent with a surround facilitation (rather than suppression) response profile. White matter tract reconstruction obtained from high angular resolution diffusion imaging (HARDI) revealed evidence of increased mean, axial, and radial diffusivities within cortico-cortical (i.e. V1-hMT+), but not thalamo-hMT+ connections. Overall, our results suggest that global motion processing deficits in CVI may be associated with impaired signal integration and segregation mechanisms, as well as white matter integrity at the level of area hMT+., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate intereye associations of visual field (VF) defects., Methods: We selected 24-2 VF pairs of both eyes from 63,604 patients tested on the same date with mean deviation (MD) ≥ -12 dB. VFs were decomposed into one normal and 15 defect patterns previously identified using archetypal analysis. VF pattern weighting coefficients were correlated between the worse and better eyes, as defined by MD. VF defect patterns (weighting coefficients > 10%) in the better eye were predicted from weighting coefficients of the worse eye by logistic regression models, which were evaluated by area under the receiver operating characteristic curve (AUC)., Results: Intereye correlations of archetypal VF patterns were strongest for the same defect pattern between fellow eyes. The AUCs for predicting the presence of 15 defect patterns in the better eye based on the worse eye ranged from 0.69 (superior nasal step) to 0.92 (near total loss). The AUC for predicting superior paracentral loss was 0.89. Superior paracentral loss in the better eye was positively correlated with coefficients of superior paracentral loss, central scotoma, superior altitudinal defect, nasal hemianopia, and inferior paracentral loss in the worse eye, and negatively correlated with coefficients of the normal VF, superior peripheral defect, concentric peripheral defect, and temporal wedge. The parameters are presented in the descending order of statistical significance., Conclusions: VF patterns of the worse eye are predictive of VF defects in the better eye., Translational Relevance: Our models can potentially assist clinicians to better interpret VF loss under measurement uncertainty., Competing Interests: Disclosure: B. Teng, None; D. Li, None; E.Y. Choi, None; L.Q. Shen, U.S. Provisional Application No. 62/909,386 (P), U.S. Application No. 036770-572001WO (P), U.S. Provisional Application No. 62/909,386 (P); L.R. Pasquale, Bausch+Lomb (P), Eyenovia (P), Nicox and Emerald Bioscience (P); M.V. Boland, None; P. Ramulu, None; S.R. Wellik, None; C.G. De Moraes, None; J.S. Myers, None; S. Yousefi, None; T. Nguyen, None; Y. Fan, None; H. Wang, None; P.J. Bex, PCT/US2014/052414 (P); T. Elze, PCT/US2014/052414 (P), U.S. Provisional Application No. 62/909,386 (P), U.S. Application No. 036770-572001WO (P), U.S. Provisional Application No. 62/804,903 (P), U.S. Provisional Application No. 62/909,386 (P); M. Wang, U.S. Provisional Application No. 62/909,386 (P), U.S. Application No. 036770-572001WO (P), U.S. Provisional Application No. 62/804,903 (P), U.S. Provisional Application No. 62/909,386 (P), (Copyright 2020 The Authors.)

Purpose: The purpose of this study was to classify the spatial patterns of retinal nerve fiber layer thickness (RNFLT) and assess their associations with visual field (VF) loss in glaucoma., Methods: We used paired reliable 24-2 VFs and optical coherence tomography scans of 691 eyes from 691 patients. The RNFLT maps were used to determine the RNFLT patterns (RPs) by non-negative matrix factorization (NMF). The RPs were correlated with mean deviation (MD), spherical equivalent (SE), and major blood vessel locations. The RPs were further used to predict the 52 total deviation (TD) values by linear regression compared with models using 24 15-degree sectors. Last, we associated the RPs with average TDs of the central upper two locations (C2-TD). Stepwise regression was applied to remove redundant features., Results: NMF highlighted 16 distinct RPs. Twelve RPs had arcuate-like informative zones (iZones): six with superior iZones, five with inferior iZones, and one RP with a bi-hemifield iZone, and four with non-arcuate-like temporal or nasal iZones. Twelve, nine, nine, and nine RPs were significantly ( P < 0.05) correlated to MD, SE, and superior and inferior artery locations, respectively. Using RPs significantly ( P < 0.05) improved the prediction of 52 TDs compared with using 24 15-degree sectors. Using RPs significantly ( P < 0.001) improved the C2-TD prediction related to thinning in the inferior vulnerability zone compared with using the 24 sectoral RNFLTs., Conclusions: Using RPs improved the VF prediction compared with using sectoral RNFLTs., Translational Relevance: The RPs characterizing both pathological and anatomical variations can potentially assist clinicians better assess RNFLT loss., Competing Interests: Disclosure: M. Wang, None; L.Q. Shen, None; L.R. Pasquale, None; H. Wang, None; D. Li, None; E.Y. Choi, None; S. Yousefi, None; P.J. Bex, None; T. Elze, None, (Copyright 2020 The Authors.)

Reading is a primary problem for low vision patients and a common functional endpoint for eye disease. However, there is limited agreement on reading assessment methods for clinical outcomes. Many clinical reading tests lack standardized materials for repeated testing and cannot be self-administered, which limit their use for vision rehabilitation monitoring and remote assessment. We compared three different reading assessment methods to address these limitations. Normally sighted participants ( N = 12) completed MNREAD, and two forced-choice reading tests at multiple font sizes in counterbalanced order. In a word identification task, participants indicated whether 5-letter pentagrams, syntactically matched to English, were words or non-words. In a true/false reading task, participants indicated whether four-word sentences presented in RSVP were logically true or false. The reading speed vs. print size data from each experiment were fit by an exponential function with parameters for reading acuity, critical print size and maximum reading speed. In all cases, reading speed increased quickly as an exponential function of text size. Reading speed and critical print size significantly differed across tasks, but not reading acuity. Reading speeds were faster for word/non-word and true/false reading tasks, consistent with the elimination of eye movement load in RSVP but required larger text sizes to achieve those faster reading speeds. These different reading tasks quantify distinct aspects of reading behavior and the preferred assessment method may depend on the goal of intervention. Reading performance is an important clinical endpoint and a key quality of life indicator, however, differences across methods complicate direct comparisons across studies., (Copyright © 2020 Arango, Yu, Lu and Bex.)

Purpose: To quantify the central visual field (VF) loss patterns in glaucoma using artificial intelligence., Design: Retrospective study., Participants: VFs of 8712 patients with 13 951 Humphrey 10-2 test results from 13 951 eyes for cross-sectional analyses, and 824 patients with at least 5 reliable 10-2 test results at 6-month intervals or more from 1191 eyes for longitudinal analyses., Methods: Total deviation values were used to determine the central VF patterns using the most recent 10-2 test results. A 24-2 VF within a 3-month window of the 10-2 tests was used to stage eyes into mild, moderate, or severe functional loss using the Hodapp-Anderson-Parrish scale at baseline. Archetypal analysis was applied to determine the central VF patterns. Cross-validation was performed to determine the optimal number of patterns. Stepwise regression was applied to select the optimal feature combination of global indices, average baseline decomposition coefficients from central VFs archetypes, and other factors to predict central VF mean deviation (MD) slope based on the Bayesian information criterion (BIC)., Main Outcome Measures: The central VF patterns stratified by severity stage based on 24-2 test results and a model to predict the central VF MD change over time using baseline test results., Results: From cross-sectional analysis, 17 distinct central VF patterns were determined for the 13 951 eyes across the spectrum of disease severity. These central VF patterns could be divided into isolated superior loss, isolated inferior loss, diffuse loss, and other loss patterns. Notably, 4 of the 5 patterns of diffuse VF loss preserved the less vulnerable inferotemporal zone, whereas they lost most of the remaining more vulnerable zone described by the Hood model. Inclusion of coefficients from central VF archetypical patterns strongly improved the prediction of central VF MD slope (BIC decrease, 35; BIC decrease of >6 indicating strong prediction improvement) than using only the global indices of 2 baseline VF results. Eyes with baseline VF results with more superonasal and inferonasal loss were more likely to show worsening MD over time., Conclusions: We quantified central VF patterns in glaucoma, which were used to improve the prediction of central VF worsening compared with using only global indices., (Copyright © 2019 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

The binocular coordination of eye movements in a three-dimensional environment involves a combination of saccade and vergence movements. To maintain binocular accuracy and control in the face of sensory and motor changes (that occur with e.g., normal aging, surgery, corrective lenses), the oculomotor system must adapt in response to manifest visual errors. This may be achieved through a combination of binocular and monocular mechanisms, including the recalibration of saccade and vergence amplitudes in response to different visual errors induced in each eye (Maiello, Harrison, & Bex, 2016). This work has used a double-step paradigm to recalibrate eye movements in response to visual errors produced by dichoptic target steps (e.g., leftward in the left eye and rightward in the right eye). Here, we evaluated the immediate perceptual effects of this adaptation. Experiment 1 measured localization errors following adaptation by comparing the apparent locations of pre- and postsaccadic probes. Consistent with previous work showing localization errors following saccadic adaptation, our results demonstrated that adaptation to a dichoptic step produces different localization errors in the two eyes. Furthermore, in Experiment 2, this effect was reduced for a vergence shift in the absence of a saccade, indicating that saccade programming is responsible for a large component of this illusory shift. Experiment 3 measured postsaccadic stereopsis thresholds and indicated that, unlike localization judgments, adaptation did not influence stereoacuity. Together, these results demonstrate novel dichoptic visual errors following oculomotor adaptation and point to monocular and binocular mechanisms involved in the maintenance of binocular coordination.

The human visual system is foveated: we can see fine spatial details in central vision, whereas resolution is poor in our peripheral visual field, and this loss of resolution follows an approximately logarithmic decrease. Additionally, our brain organizes visual input in polar coordinates. Therefore, the image projection occurring between retina and primary visual cortex can be mathematically described by the log-polar transform. Here, we test and model how this space-variant visual processing affects how we process binocular disparity, a key component of human depth perception. We observe that the fovea preferentially processes disparities at fine spatial scales, whereas the visual periphery is tuned for coarse spatial scales, in line with the naturally occurring distributions of depths and disparities in the real-world. We further show that the visual system integrates disparity information across the visual field, in a near-optimal fashion. We develop a foveated, log-polar model that mimics the processing of depth information in primary visual cortex and that can process disparity directly in the cortical domain representation. This model takes real images as input and recreates the observed topography of human disparity sensitivity. Our findings support the notion that our foveated, binocular visual system has been moulded by the statistics of our visual environment., Competing Interests: The authors have declared that no competing interests exist.

Importance: Although the central visual field (VF) in end-stage glaucoma may substantially vary among patients, structure-function studies and quality-of-life assessments are impeded by the lack of appropriate characterization of end-stage VF loss., Objective: To provide a quantitative characterization and classification of central VF loss in end-stage glaucoma., Design, Setting, and Participants: This retrospective cohort study collected data from 5 US glaucoma services from June 1, 1999, through October 1, 2014. A total of 2912 reliable 10-2 VFs of 1103 eyes from 1010 patients measured after end-stage 24-2 VFs with a mean deviation (MD) of -22 dB or less were included in the analysis. Data were analyzed from March 28, 2018, through May 23, 2019., Main Outcomes and Measures: Central VF patterns were determined by an artificial intelligence algorithm termed archetypal analysis. Longitudinal analyses were performed to investigate whether the development of central VF defect mostly affects specific vulnerability zones., Results: Among the 1103 patients with the most recent VFs, mean (SD) age was 70.4 (14.3) years; mean (SD) 10-2 MD, -21.5 (5.6) dB. Fourteen central VF patterns were determined, including the most common temporal sparing patterns (304 [27.5%]), followed by mostly nasal loss (280 [25.4%]), hemifield loss (169 [15.3%]), central island (120 [10.9%]), total loss (91 [8.3%]), nearly intact field (56 [5.1%]), inferonasal quadrant sparing (42 [3.8%]), and nearly total loss (41 [3.7%]). Location-specific median total deviation analyses partitioned the central VF into a more vulnerable superonasal zone and a less vulnerable inferotemporal zone. At 1-year and 2-year follow-up, new defects mostly occurred in the more vulnerable zone. Initial encroachments on an intact central VF at follow-up were more likely to be from nasal loss (11 [18.4%]; P < .001). One of the nasal loss patterns had a substantial chance at 2-year follow-up (8 [11.0%]; P = .004) to shift to total loss, whereas others did not., Conclusions and Relevance: In this study, central VF loss in end-stage glaucoma was found to exhibit characteristic patterns that might be associated with different subtypes. Initial central VF loss is likely to be nasal loss, and 1 specific type of nasal loss is likely to develop into total loss.

The complete assessment of vision-related abilities should consider visual function (the performance of components of the visual system) and functional vision (visual task-related ability). Assessment methods are highly dependent upon individual characteristics (eg, the presence and type of visual impairment). Typical visual function tests assess factors such as visual acuity, contrast sensitivity, color, depth, and motion perception. These properties each represent an aspect of visual function and may impact an individual's level of functional vision. The goal of any functional vision assessment should be to measure the visual task-related ability under real-world scenarios. Recent technological advancements such as virtual reality can provide new opportunities to improve traditional vision assessments by providing novel objective and ecologically valid measurements of performance, and allowing for the investigation of their neural basis. In this review, visual function and functional vision evaluation approaches are discussed in the context of traditional and novel acquisition methods., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Amblyopia is associated with a range of well-known visual spatial deficits, which include reduced contrast sensitivity, spatial distortions, interocular suppression, and impaired stereopsis. Previous work has also pointed to deficits in processing dynamic visual information, but it is unknown whether these deficits influence performance under binocular conditions. We examined the effects of temporal modulation on contrast sensitivity and binocular interactions in a preliminary study of 8 adults with amblyopia and 14 normally-sighted control subjects. For each observer, we measured interocular balance and stereopsis thresholds with binocular flicker across a range of four temporal (0, 4, 7.5, and 12 Hz) and spatial (1, 2, 4, and 8 cpd) frequencies. Interocular balance was estimated by varying the relative contrast of dichoptic letter pairs to produce perceptual reports of each letter with equal frequency, and stereopsis thresholds were measured by determining the minimum disparity at which subjects identified a front-depth target with 75% accuracy. Consistent with previous findings, we observed greater interocular imbalance and impaired stereoacuity at high spatial frequencies in amblyopes. In contrast, the effects of temporal frequency on performance were smaller: across both groups, interocular imbalance was largest at mid-to-low temporal frequencies, and stereopsis thresholds were unaffected by temporal frequency. Our results suggest that there may be a previously unreported effect of temporal frequency on interocular balance, as well as a possible dissociation between the effects of flicker on interocular balance and stereopsis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Purpose : Amblyopia and strabismus affect 2%-5% of the population and cause a broad range of visual deficits. The response to treatment is generally assessed using visual acuity, which is an insensitive measure of visual function and may, therefore, underestimate binocular vision gains in these patients. On the other hand, the contrast sensitivity function (CSF) generally takes longer to assess than visual acuity, but it is better correlated with improvement in a range of visual tasks and, notably, with improvements in binocular vision. The present study aims to assess monocular and binocular CSFs in amblyopia and strabismus patients. Methods : Both monocular CSFs and the binocular CSF were assessed for subjects with amblyopia ( n = 11), strabismus without amblyopia ( n = 20), and normally sighted controls ( n = 24) using a tablet-based implementation of the quick CSF, which can assess a full CSF in <3 min. Binocular summation was evaluated against a baseline model of simple probability summation. Results : The CSF of amblyopic eyes was impaired at mid-to-high spatial frequencies compared to fellow eyes, strabismic eyes without amblyopia, and control eyes. Binocular contrast summation exceeded probability summation in controls, but not in subjects with amblyopia (with or without strabismus) or strabismus without amblyopia who were able to fuse at the test distance. Binocular summation was less than probability summation in strabismic subjects who were unable to fuse. Conclusions : We conclude that monocular and binocular contrast sensitivity deficits define important characteristics of amblyopia and strabismus that are not captured by visual acuity alone and can be measured efficiently using the quick CSF.

Reading is a crucial visual activity and a fundamental skill in daily life. Rapid Serial Visual Presentation (RSVP) is a text-presentation paradigm that has been extensively used in the laboratory to study basic characteristics of reading performance. However, measuring reading function (reading speed vs. print size) is time-consuming for RSVP reading using conventional testing procedures. In this study, we develop a novel method, qReading, utilizing the Bayesian adaptive testing framework to measure reading function in the periphery. We perform both a psychophysical experiment and computer simulations to validate the qReading method. In the experiment, words are presented using an RSVP paradigm at 10° in the lower visual field. The reading function obtained from the qReading method with 50 trials exhibits good agreement (i.e., high accuracy) with the reading function obtained from a conventional method (method of constant stimuli [MCS]) with 186 trials (mean root mean square error: 0.12 log10 units). Simulations further confirm that the qReading method provides an unbiased measure. The qReading procedure also demonstrates excellent precision (half width of 68.2% credible interval: 0.02 log10 units with 50 trials) compared to the MCS method (0.03 log10 units with 186 trials). This investigation establishes that the qReading method can adequately measure the reading function in the normal periphery with high accuracy, precision, and efficiency, and is a potentially valuable tool for both research and clinical assessments.

The visual system is required to compute objects from partial image structure so that figures can be segmented from their backgrounds. Although early clinical, behavioral, and modeling data suggested that such computations are performed pre-attentively, recent neurophysiological evidence suggests that surface filling-in is influenced by attention. In the present study we developed a variant of the classical Kanizsa illusory triangle to investigate whether voluntary attention modulates perceptual filling-in. Our figure consists of "pacmen" positioned at the tips of an illusory 6-point star and alternating in polarity such that two illusory triangles are implied to compete with one another within the figure. On each trial, observers were cued to attend to only one triangle, and then compared its lightness with a matching texture-defined triangle. We found that perceived lightness of the illusory shape depended on the polarity of pacmen framing the attended triangle. Our findings thus reveal that, for overlapping illusory surfaces, lightness judgements can depend on voluntary attention. Our novel stimulus may prove useful in future attempts to link neurophysiological effects to phenomenology.

Orientation and position of small image segments are considered to be two fundamental low-level attributes in early visual processing, yet their encoding in complex natural stimuli is underexplored. By measuring the just-noticeable differences in noise perturbation, we investigated how orientation and position information of a large number of local elements (Gabors) were encoded separately or jointly. Importantly, the Gabors composed various classes of naturalistic stimuli that were equated by all low-level attributes and differed only in their higher-order configural complexity and familiarity. Although unable to consciously tell apart the type of perturbation, observers detected orientation and position noise significantly differently. Furthermore, when the Gabors were perturbed by both types of noise simultaneously, performance adhered to a reliability-based optimal probabilistic combination of individual attribute noises. Our results suggest that orientation and position are independently coded and probabilistically combined for naturalistic stimuli at the earliest stage of visual processing., Competing Interests: The authors have declared that no competing interests exist.